Large land based artillery and naval gun systems often employ a multi-step loading process in which the projectile and the propellant charge are separately loaded into the firing chamber and subsequently mated together within the firing chamber. Separately loading the propellant charges allows operators of a gun system to adjust the amount of propellant loaded depending on the intended travel distance of the projectile and other firing conditions. Propellant charges can be loaded as a single charge or as a plurality of smaller charges depending on the firing requirements. While separately loading the propellant charges significantly increases the flexibility of long ranged gun systems, the introduction of automated reloading systems and new strategies for using gun systems have created new problems not previously encountered that may interfere or conflict with the traditional multi-step loading process.
In many gun systems, the propellant charges are first loosely loaded into a cartridge case before the entire cartridge assembly is loaded into the firing chamber and mated to the projectile. The cartridge case may include an integrated primer for igniting the propellant charges. Wadding or a plug is often placed over the opening of the cartridge case to ensure that the maximum force of the generated gases from the ignited propellant charges is directed against the projectile. The wadding or plug assists in sealing the expanding propellant gases behind the projectile. While preloading the propellant charges into a cartridge case simplifies the reloading process by allowing operators or automated reloading machinery to handle a single cartridge assembly instead of a plurality of small charges, maintaining the propellant charges within the cartridge case during loading is often difficult.
During loading, a cartridge assembly is chambered by either a manual or a powered ramrod to ram the cartridge assembly into the firing chamber and against the projectile. As the propellant charges for large gun systems can often weigh dozens of pounds, the inertia of the moving propellant charges can cause the propellant charges to continue moving forward even after the rim of the cartridge case is abutted to the base of the projectile. The forward motion of the propellant charges can cause the cartridge cap or wadding to be displaced or the propellant charges to escape the cartridge case.
Propellant charges can be preloaded into a combustible bag before the charges are placed in the cartridge case to help keep the propellant charges together during loading and firing. However, this approach adds an additional step to the reloading process, potentially increasing the reloading time of the gun system. Furthermore, fitting the combustible bag over the propellant charges and within the cartridge case without blocking the interface between the projectile and the cartridge case can be difficult. The presence of a primer in the cartridge case can also interfere with the use of the bag. As such, there is still room for improvement in within cartridge cases.